Aquaporin 1 is expressed in the human endometrium during normal cycle and increases after mifepristone treatment
Anna Hildenbrand1, Anneli Stavreus-Evers, P G L Lalitkumar
1Division of Woman and Child Health, Karolinska Institutet, Stockholm, Sweden. anna.hildenbrand@ki.se
Abstract:
Aquaporin-1 (AQP1) is involved in the angiogenesis and structural modifications of microvessels and possibly also in the pathogenesis of idiopathic menhorrhagia, where a reduced AQP1 expression is seen in the endometrium. Mifepristone treatment induces reduced menstrual bleeding and amenorrhea and also has a direct effect on endometrial arterioles. Administered with gestagen-only contraceptive methods, antiprogestins improve the bleeding pattern. The objective of this study was to evaluate the AQP1 expression in endometrial blood vessels during normal cycle and after mifepristone treatment. Localization and expression of AQP1 was determined using immunohistochemistry and reverse transcriptase chain reaction (RT-PCR) in 43 biopsies from human endometrium taken during a normal cycle and after mifepristone treatment. AQP1 expression in human endometrial vessels is not cycle dependent and is stronger in capillaries and arteries than in veins. After mifepristone treatment the staining intensity was increased, but not the number of stained vessels. The presence of AQP1 was also confirmed using RT-PCR. The changes in AQP1 expression could contribute to the reduced bleeding seen following mifepristone treatment and could be an effect of either antagonizing progesterone or cortisol.
Related Concept Videos
Aquaporins
Hormonal Regulation of the Menstrual Cycle
At puberty, GnRH begins a pulsatile release pattern, which triggers the anterior pituitary gland to secrete follicle-stimulating hormone (FSH) and luteinizing hormone (LH). The frequency and amplitude of GnRH pulses vary across the menstrual cycle, with faster pulses favoring LH release and slower pulses favoring FSH release.
Ovarian Cycle
Secretory Phase
Following ovulation, the corpus luteum, a temporary endocrine structure, produces progesterone and estrogens. These hormones stimulate the growth and coiling of endometrial...
Proliferative Phase
Notably, the stratum basale, the basal layer of the endometrium, including the basal parts of the uterine glands, remains unaffected by menstruation. Stem cells in this layer undergo mitosis, regenerating the stratum functionalis and thickening the...
Menses Phase
When fertilization does not occur, the corpus luteum deteriorates, causing a significant drop in the levels of estrogen and progesterone in the body. This hormonal decrease triggers the release of prostaglandins, which cause the uterine...
